Swivel assembly

ABSTRACT

A swivel assembly for use with a chair has a swivel that includes an actuator which biases and self-centers the swivel to a start or zero position wherein the swivel is rotated from its start or zero position in either a clockwise or counterclockwise manner to an alternate position. When the swivel is released the actuator biases the swivel back to its start or zero position. A method for self-centering swiveling of a chair includes providing a swivel that has an actuator which self-centers and biases the swivel to a start or zero position; rotating the swivel from its start or zero position, thus compressing or tensioning the actuator; and releasing the swivel thus moving the actuator to bias and rotate the swivel back to its start or zero position.

CLAIM OF PRIORITY

This application claims priority from and benefit of the filing date of U.S. Provisional Patent Application Ser. No. 61/430,371, filed on Jan. 6, 2011, which is hereby incorporated by reference in its entirety.

FIELD OF DISCLOSURE

The disclosure relates to a swivel assembly for a chair or other application. More particularly, it relates to a full rotation swivel assembly (sometimes referred to herein as a “swivel”) that uses a gas spring or a mechanical spring (e.g., a compression coil spring or a tension spring) or other actuator that self centers to a zero or starting position.

The disclosure relates to a chair which can be rotated in a circular movement from a fixed position while the person is seated in the chair. More specifically, as discussed hereinbelow, the subject disclosure is particularly applicable to lounge chairs which are commonly found in casinos and is directed to those types of chairs, which can be rotated by the person seated in the chair while seated therein. However, the disclosure is not limited to lounge chairs or chairs in particular.

BACKGROUND

Rotatable chairs have existed for years and most persons are familiar with chairs which can be rotated manually by foot or other movements. Additionally, some chairs such as barber chairs can be rotated by the action of a pneumatically operated system. Other such variations on this concept also exist.

A chair often is viewed as a piece of furniture including a seat, legs, back, and often arms, designed to accommodate one person. A swivel chair may further include a seat connected to a bearing that swivels about a stationary post connected to a base. A flat cylindrical bearing swivel provides rotational movement while a tilt cylindrical bearing swivel additionally permits the user to pitch the seat back and forth.

Some swivel chairs include a pre-molded plastic seat connected to a seat support that includes an opening and a stationary post connected to a base. The opening of the seat support is aligned over the stationary post so that the stationary post is concentric with the seat support opening.

There exists a need for a full rotation chair swivel assembly that uses a gas spring and/or a compression or tension spring that self centers the swivel assembly to a zero or starting position, which overcomes deficiencies in existing swivel assemblies while providing improved overall results.

SUMMARY OF DISCLOSURE

The disclosure relates to simple and cost-effective chair swivel assemblies. More particularly, it relates to a full rotation chair swivel which uses an actuator such as a gas spring and/or a compression coil or tension spring that self centers to a zero or starting position.

In accordance with one aspect of the disclosure, a swivel chair has a full rotation swivel that uses a gas spring or the like to self center the swivel chair to a “home” or start or zero position. When the swivel is rotated to any position with respect to the home position, either clockwise or counterclockwise, and released, the gas spring or compression spring rotates the swivel back to the home or zero position. The swivel can rotate clockwise or counterclockwise to any position from 0° to 360°, and allows for unlimited rotations prior to releasing the swivel.

In accordance with another aspect of the disclosure, the swivel is used for chairs but can be used for rotating other pieces of furniture or other objects as well.

In accordance with another aspect of the disclosure, the swivel can be made of two plates, one stationary plate and a plate that rotates.

In accordance with another aspect of the disclosure, the swivel has one end of a gas spring (or gas strut) attached to or adjacent the stationary plate either directly or through the use of a bolt or other fastener. The other end of the gas spring is attached to the rotating plate.

When swivel rotates from the home or zero position, the gas spring is compressed. The spring can be a standard spring or spring mechanism. When released due to compression, the compressed gas contained within the gas spring forces the swivel back to a home position. The gas spring can also have dampening characteristics to better control the speed at which the swivel rotates back to the home position.

Still another aspect of the disclosure is the swivel can be used with chairs and the swivel mechanism is placed between the base of the chair and the underside of the seat. The swivel rotates the chair back to its home, forward facing or zero position. Casinos and bars utilize this swivel mechanism to keep chairs or bar stools lined up in a neat, orderly fashion.

In accordance with another aspect of the disclosure, a swivel assembly for use with a chair includes a swivel that has an actuator which biases and self-centers the swivel to a start or zero position. The swivel is rotated from its start to zero position in either a clockwise or counterclockwise manner to an alternate position. When the swivel is released the actuator biases the swivel back to the start or zero position.

In accordance with another aspect of the disclosure, a method for self-centering swiveling of a chair includes providing a swivel that comprises an actuator which self-centers and biases the swivel to a start or zero position; rotating the swivel from its start or zero position, thus compressing or tensioning the actuator; and releasing the swivel thus moving the actuator to bias and rotate the swivel back to its start or zero position.

Another aspect of the disclosure is a seat swivel with limitless rotation and a biasing means to return it to a home position. This feature is desirable and in some instances required for safety reasons by local fire codes at certain facilities like casinos or bars.

Still other aspects of the disclosure will become apparent upon a reading and understanding of the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a top plan view of a chair swivel in a home or zero position in accordance with one aspect of the disclosure;

FIG. 1B is a side elevational view of the swivel of FIG. 1A;

FIG. 1C is a bottom plan view of the swivel of FIG. 1A;

FIG. 1D is a perspective view of the swivel of FIG. 1A;

FIG. 2 is an enlarged perspective view of the chair swivel in the home position of FIG. 1A;

FIG. 3 is an enlarged top plan view of the chair swivel of FIG. 1A;

FIG. 4 is an elongated cross-sectional view of FIG. 1B;

FIG. 5A is a top plan view of the chair swivel rotated 45 degrees clockwise from the home position of FIG. 1A;

FIG. 5B is a side elevational view of the swivel of FIG. 5A;

FIG. 5C is a bottom plan view of the swivel of FIG. 5A;

FIG. 5D is a perspective view of the swivel of FIG. 5A;

FIG. 6 is an enlarged top plan view of the chair swivel of FIG. 5A;

FIG. 7A is a top plan view of the chair swivel rotated 90 degrees clockwise from the home position of FIG. 1A;

FIG. 7B is a side elevational view of the swivel of FIG. 7A;

FIG. 7C is a bottom plan view of the swivel of FIG. 7A;

FIG. 7D is a perspective view of the swivel of FIG. 7A;

FIG. 8 is an enlarged top plan view of the chair swivel of FIG. 7A;

FIG. 9A is a top plan view of the chair swivel rotated 135 degrees clockwise from the home position of FIG. 1A;

FIG. 9B is a side elevational view of the swivel of FIG. 9A;

FIG. 9C is a bottom plan view of the swivel of FIG. 9A;

FIG. 9D is a perspective view of the swivel of FIG. 9A;

FIG. 10 is an enlarged top plan view of the chair swivel of FIG. 9A;

FIG. 11A is a top plan view of the chair swivel rotated 180 degrees clockwise from the home position of FIG. 1A;

FIG. 11B is a side elevational view of the swivel of FIG. 11A;

FIG. 11C is a bottom plan view of the swivel of FIG. 11A;

FIG. 11D is a perspective view of the swivel of FIG. 11A;

FIG. 12 is an enlarged top plan view of the chair swivel of FIG. 11A;

FIG. 13 is an enlarged cross-sectional view of FIG. 11B;

FIG. 14A is a top plan view of the chair swivel rotated 90 degrees counterclockwise from the home position of FIG. 1A;

FIG. 14B is a side elevational view of the swivel of FIG. 11A;

FIG. 14C is a bottom plan view of the swivel of FIG. 11A;

FIG. 14D is a perspective view of the swivel of FIG. 11A;

FIG. 15 is an enlarged top plan view of the chair swivel of FIG. 14A;

FIG. 16 is a cross-sectional view of an alternate embodiment of the swivel assembly using a compression spring with the spring in an uncompressed state;

FIG. 17 is a cross-sectional view of the swivel assembly of FIG. 16 with the spring in a highly compressed state;

FIG. 18 is a cross-sectional view of another alternate embodiment of the swivel assembly with a compression spring surrounding the piston rod and using an alternative home position with the spring in an uncompressed state;

FIG. 19 is a cross-sectional view for the embodiment of FIG. 18 with the compression spring in a highly compressed state;

FIG. 20 is a cross-sectional view of another alternate embodiment of the swivel assembly using gas with the piston rod in the retracted position in a home position with the gas in an uncompressed state;

FIG. 21 is a cross-sectional view of the swivel assembly of FIG. 20 with the piston rod in the extended position and the gas highly compressed;

FIG. 22 shows another alternative embodiment of the swivel assembly that uses a tension spring to bias the swivel assembly to its home position.

DETAILED DESCRIPTION OF THE DISCLOSURE

The disclosure relates to a swivel assembly for a chair or other application. It is described herein primarily with reference to use as a chair swivel assembly. More particularly, the disclosure relates to a full rotation swivel assembly or “swivel” that uses a gas spring or a mechanical spring (e.g., a compression spring or tension spring) that self centers the swivel assembly to a zero or starting position.

The swivel chair has a full rotation swivel that uses a gas spring or a mechanical spring such as a compression coil spring or a tension spring to self center the swivel chair to a “home” or start or zero position. When the swivel is rotated to any position with respect to the home position, either clockwise or counterclockwise, and released, the gas or compression spring rotates the swivel back to the home or zero position. The swivel can rotate clockwise or counterclockwise to any position from 0° to 360°, and allows for unlimited rotations prior to releasing the swivel. Those of ordinary skill in the art will recognize that the swivel or swivel assembly disclosed herein rotates bi-directionally without any limit to its rotation in either the clockwise or counterclockwise direction, and further that each reference to a particular clockwise angle of rotation used herein can be replaced with a corresponding counterclockwise angle of rotation and vice versa.

When the swivel rotates from the home or zero position, the gas spring is actuated or compressed. The spring can be a standard gas spring or gas spring mechanism or, alternatively, can be a standard mechanical spring or spring assembly defined by or comprising a compression spring or a tension spring (e.g., a wire coil spring). When the swivel is released, the compressed gas contained within the gas spring (or the biasing force of the mechanical spring) forces the swivel back to a home position. The gas spring can also have dampening characteristics to better control the speed at which the swivel rotates back to the home position.

The swivel can be used with chairs and the swivel mechanism is placed between the chair legs or stand (the base of the chair) and the underside of the seat. The swivel rotates the chair back to its home, forward facing or zero position.

Referring now to FIGS. 1A-1D, a chair swivel assembly 10 in accordance with one embodiment of the disclosure is shown in various views. The assembly preferably includes a pair of parallel spaced apart chair mounting metal brackets 12, 14, each of which has a pair of spaced apart holes 16, 18 that can be slots or circular apertures or otherwise shaped openings adapted for mounting an underside of a chair (or other structure) (not shown) to the brackets with suitable fasteners such as screws.

A third metal bracket 20 extends between the first and second brackets for lateral reinforcement. The bracket 20 is substantially perpendicular to first and second brackets 12, 14.

Referring to FIG. 1B, a lower portion of the assembly includes a rotatable upper plate 22 and a parallel stationary lower plate 24 both preferably made of metal. Referring to FIG. 1C, leg posts or other parts of the fixed chair base are mounted to holes or slots 26 formed on four corners of the lower plate. A support plate 28 preferably made of metal extends from upper plate 22 and/or is connected to the brackets 12, 14, 20 in any suitable fashion. Plate 28 is shown as triangular in shape, but other shapes are also contemplated by the disclosure. An outer or first end 36 of an actuator 30 such as a gas spring is fixably connected to the support plate 28 in any suitable manner. (See FIGS. 2 and 3).

Referring now to FIG. 4, an inner or second end 48 of the actuator or gas spring 30 is mounted to a fixed tab 50 which is fixed in position relative to the lower plate 24. As shown herein, the tab 50 is connected to or defined as part of a cap 51 that is used to capture the upper plate 22 to the lower plate 24. A rivet or other suitable fastener 53 rotatably connects the upper plate 22 to the lower plate 24 and secures the cap 51 in a fixed position relative to the lower plate 24. A post or stud 52 projects upwardly from the tab 50 and provides a mounting location for pivotally connecting the inner end 48 of the gas spring 30 to the tab 50. Alternatively, tab 50 can be part of the lower plate 24.

Referring still to FIG. 4, roller or ball or other bearings 54 are mounted in races or cavities 58 formed by opposed curved portions of the upper and lower plates 22, 24, facilitating rotation of the upper plate 22 with respect to the lower plate 24. Bearings 56 are located in race 62 defined between the cap 51 and the upper plate 22.

The fixed tab 50 and the mounting post 52 act as an eccentric cam since they are offset relative to the central axis of rotation 68 (See FIG. 4) of the upper plate 22 or any chair connected thereto. In other words, pivoting or rotation of the outer end 36 of the gas spring 30 about the inner end 48 of the gas spring 30 is eccentric relative to the rotation of the upper plate 22 about the lower plate 24 on axis 68. As such, relative rotation of the upper plate 22 relative to the lower plate 24 induces extension or retraction of the gas spring 30 as described below.

With continuing reference to FIG. 4, the gas spring 30 includes a rod 32 which extends and retracts relative to an inner chamber or bore 40 of housing 34. Outer end 36 of housing 34 is mounted to a post 38 which extends from support plate 28. At a first or inner end 42 of the rod is a piston 44 which pushes or compresses either gas or a mechanical spring located between the piston 44 and an inner wall 46 of the housing and a first end inner wall 47 of the housing. As shown in FIG. 4, piston 44 can have an opening or orifice 45 formed therethrough which air or fluid such as oil may pass or flow through at a controlled rate to damper or cushion the rotation of the swivel. The dampening may also be asymmetrical, i.e., the dampening may be greater in one direction of rotation or another. Furthermore, any of the pistons shown in the figures may have an opening or orifice for providing the dampening feature.

Gas is captured to the right (as shown in FIG. 4) of piston 44 within the bore 40 between the piston housing 44 and inner end wall 47. The rod is extended out of the housing in this start or zero position in this “push” type actuator. As the rod and piston moves into the housing (i.e., to the right of FIG. 4), gas between piston 44 and housing end wall 47 becomes more and more compressed. As the swivel assembly continues to rotate in a clockwise or counterclockwise manner, the gas becomes more and more compressed by the piston 44 such that the swivel rotates back to its home or zero position as shown in FIG. 4 when any external force on the swivel is removed. It should be noted that phrases such as “the swivel rotates” and “rotation of the swivel” refer to rotation of the upper plate 22 and the components connected thereto relative to the lower plate 24.

For example, referring now to FIGS. 5A-5D and 6, the swivel assembly is shown rotated to 45° clockwise from the home or zero position. This moves the piston 44 further into opening 40 of housing 34, thus compressing the gas in the housing between piston 44 and end wall 47. If the swivel is released, the compressed gas would move the piston 44 outward relative to the housing 34, thus extending the rod further out of the housing and rotating the swivel counterclockwise back to the home position.

Similarly, referring now to FIGS. 7A-7D and 8, the swivel assembly is shown rotated to 90° clockwise from the home or zero position. This moves the piston 44 further into opening 40 of housing 34, thus even further compressing the gas between piston 44 and end wall 47.

If released, the compressed gas would move the piston 44 outward relative to the housing 34, thus extending the rod further out of the housing and rotating the swivel counterclockwise back to the home position.

Referring now to FIGS. 9A-9D and 10, the swivel assembly is rotated 135° clockwise from the home or zero position. This moves the piston 44 even further into housing opening 40, thus further compressing the gas between the piston 44 and end wall 47. If released, the compressed gas would move the piston back out of the housing, thus extending the rod further out of the housing and rotating the swivel counterclockwise back to the home position.

Referring now to FIGS. 11A-11D, 12, and 13, the swivel assembly is shown rotated 180° clockwise or counterclockwise from the home or zero position of FIGS. 1A-1D. The piston 44 is moved even further into bore 40, thus highly compressing the gas between piston 44 and housing end wall 47 as seen in FIG. 13. When the swivel is released, the highly compressed gas pushes the piston 44 outward relative to the bore 40 which in turn extends the rod out of the housing and rotates the swivel clockwise or counterclockwise back to the home or zero position. The swivel can keep rotating clockwise beyond 180° at which time the piston 44 begins to move outward in the bore 40. Those of ordinary skill in the art will recognize that it is theoretically possible that the swivel assembly will balance or stall or stick in the 180° position until moved in either the clockwise or counterclockwise position slightly by outside forces, although this is unlikely in real-world situations. The use of the term “self center” or the like herein is intended to include this possibility, i.e., the fact that a swivel assembly might stick or stall in the 180° rotated position does not prevent same from falling within the scope of the present development.

Referring now to FIGS. 14A-14B and 15, the swivel assembly is now shown rotated 90° counterclockwise from the home or zero position. Again, this will push the piston 44 into bore 40, which compresses gas between the piston 44 and wall 47. When released, the swivel will rotate clockwise back to the home position shown in FIG. 4.

Referring now to FIGS. 16-17, an alternate embodiment of the swivel with a “push” type actuator is shown. Instead of compressed gas, the actuator is formed by a standard compression spring 70 such as a coil spring is positioned between piston 44 and inner end wall 47 of housing 34. FIG. 16 shows the actuator or spring 70 in an uncompressed or less compressed state. Again, the rod is extended from the housing in the start or zero position. As the swivel assembly is rotated either clockwise or counterclockwise, the spring 70 becomes more compressed by movement of the piston 44 into bore 40 toward end wall 47 (i.e., to the right of FIG. 16). As shown in FIG. 17, the actuator or spring 70 becomes highly compressed as the piston enters the bore 40. When the swivel is released, the spring 70 resiliently returns to its unbiased or uncompressed or less compressed state, thus extending the rod out of the housing and rotating the swivel back to its home position as seen in FIG. 16.

Referring now to FIGS. 18 and 19, another alternate embodiment of the swivel is shown. In this case, FIG. 18 (retraction of the gas spring piston rod 32 into the housing 34) is the home or zero or start position of this “pull” type actuator and FIG. 19 (extension of the gas spring piston rod 32, out of housing 34) is the 180 degree rotated position. In this embodiment, a spring 72 is positioned over and surrounds rod 32 and is interposed between the piston 44 and a second inner end wall 49 (opposite to first inner end wall 47) of the housing 34. In the home position (FIG. 18), the piston 44 is extended far into bore 40 until almost adjacent end 47. The spring 72 is uncompressed in this position. As the swivel is rotated clockwise or counterclockwise, the spring 72 becomes compressed between piston 44 and inner end wall 49 as the piston rod 32 extends out of bore 40 as seen in FIG. 19. When the swivel is released, the spring 72 returns to its uncompressed or less compressed state, thus retracting the rod 32 of piston 44 into the housing and returning the swivel to its home position of FIG. 18.

Referring to FIGS. 20 and 21, another alternate embodiment of the swivel is shown. As in FIG. 18, the home or start position is 180° from the home position shown in FIG. 1. That is, in this embodiment, the piston rod 32 is extended far into the bore 40 in the home or zero or start position and the uncompressed or less compressed gas is captured between the piston 44 and end wall 49. As the swivel rotates, the piston 44 and rod 32 is extended and moved outward toward wall 49, thus compressing the gas between the piston 44 and end wall 49 until the gas is in the highly compressed state shown in FIG. 21. Upon release of external forces on the swivel, the compressed gas will force piston 44 away from wall 49 toward wall 47 which will cause the rod 32 to retract into the housing and cause the swivel to rotate back to its home position.

Other embodiments are also contemplated, such as using compression or tension springs and gas together.

Still another alternative embodiment is shown in FIG. 22. An actuator is formed by a mechanical tension spring 72′ is operably connected between the piston 44 and the housing end wall 49. FIG. 22 shows the swivel in its home position. Upon rotation of the swivel away from its home position, the tension spring 72′ will elongate and become tensioned. Upon release of the swivel, the tension spring 72′ will pull the piston 44 toward the end wall 49 to return the swivel to its home position. Alternatively, opposite ends of spring 72′ can be connected directly to plate 28 and tab 50 respectively, without containing spring 72′ in housing 34.

Those of ordinary skill in the art will recognize that the home or start position is defined when the opposite ends 36, 48 of the actuator 30 or 70 and the axis of rotation 68 of the rotating (upper) plate 22 are at least substantially aligned. If the actuator 30 or 70 is a “push” type actuator that naturally biases the rod 32 to its extended position where it extends a maximum distance from its housing 44 (i.e., an actuator that naturally seeks to assume its most elongated state), the home position will be defined when the first and second ends 36, 48 of the actuator 30 or 70 are spaced a maximum distance from each other as allowed by the swivel assembly 10. Alternatively, if the actuator 30 or 70 is a “pull” type actuator that naturally biases the rod 32 to its retracted position where it is retracted a maximum possible extent into its housing 44 (i.e., an actuator that naturally seeks to assume its most shortened state), the home position will be defined when the first and second ends 36,48 of the actuator 30 are spaced a minimum distance from each other as allowed by the swivel assembly 10.

The exemplary embodiment has been described with reference to the preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the exemplary embodiment be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof. 

1. A swivel assembly for use with an associated chair comprising: a swivel that comprises an actuator which biases and self-centers said swivel to a start or zero position; wherein said swivel is selectively rotated from its start or zero position in either a clockwise or counterclockwise manner to an alternate position; and wherein when the swivel is released said actuator biases said swivel back to said start or zero position.
 2. The swivel assembly of claim 1, wherein said actuator is a gas spring.
 3. The swivel assembly of claim 1, wherein said actuator is a compression coil spring.
 4. The swivel assembly of claim 1, wherein said swivel comprises a pair of parallel spaced apart brackets for mounting to an underside of said chair.
 5. The swivel assembly of claim 1, wherein said swivel further comprises a first plate and a second plate, wherein said first plate rotates with regard to said second plate.
 6. The swivel assembly of claim 5, wherein said swivel further comprises a support plate extending from one of said first and second plates for supporting a first end portion of said actuator.
 7. The swivel assembly of claim 6, further comprising a tab extending from said first plate for supporting a second end portion of said actuator.
 8. The swivel assembly of claim 7, further comprising a ball bearing assembly interposed between said first plate and said second plate to facilitate rotation of said first plate with respect to said second plate.
 9. The swivel assembly of claim 7, wherein said tab comprises a post for mounting said second end of said actuator.
 10. The swivel assembly of claim 9, wherein said tab and post are offset with respect to a central axis of rotation of said first plate to form an eccentric cam.
 11. The swivel assembly of claim 10, wherein rotation of said second end portion of said actuator with respect to said first end portion of said actuator is eccentric relative to said rotation of said first plate with respect to said second plate.
 12. The swivel assembly of claim 1, wherein said actuator comprises a rod and a housing, wherein said rod extends and retracts relative to said housing, wherein said rod comprises a piston at one end of said rod.
 13. The swivel assembly of claim 12, wherein said piston comprises an opening through which air or fluid can flow to dampen rotation of said swivel.
 14. The swivel assembly of claim 12, wherein said piston compresses a gas located between said piston and a first inner wall of said housing.
 15. The swivel assembly of claim 14, wherein where said swivel rotates clockwise or counterclockwise from said start position, said rod retracts into said housing, thus moving said piston toward said first inner wall of said housing compressing said gas between said piston and said first inner wall of said housing.
 16. The swivel assembly of claim 15, wherein when said swivel is released, said gas becomes uncompressed and moves said piston away from said first inner wall of said housing extending said rod out of said housing, and thus rotating said swivel back to its start position.
 17. The swivel assembly of claim 12, wherein when said piston compresses a coil spring located between said piston and a first inner wall of said housing.
 18. The swivel assembly of claim 17, wherein when said swivel rotates clockwise or counterclockwise from said start position, said rod retracts into said housing, moving said piston toward said inner first wall of said housing thus compressing said coil spring between said piston and said first inner wall of said housing.
 19. The swivel assembly of claim 18, wherein when said swivel is released, said coil spring becomes uncompressed and extends said rod out of said housing thus moving said piston away from said first inner wall of said housing, thus rotating said swivel back to its start position.
 20. The swivel assembly of claim 12, wherein said piston compresses a gas located between said piston and a second inner wall of said housing opposite a first inner wall of said housing.
 21. The swivel assembly of claim 20, wherein when said swivel rotates clockwise or counterclockwise from said start position, said rod extends out of said housing, said piston moves toward said second inner wall of said housing, thus compressing said gas between said piston and said second inner wall of said housing.
 22. The swivel assembly of claim 21, wherein when said swivel is released, said gas becomes uncompressed and moves said piston away from said second inner wall of said housing, thereby retracting said rod into said housing, thus rotating said swivel back to its start position.
 23. The swivel assembly of claim 12, wherein said piston compresses a coil spring located between said piston and a second inner wall of said housing opposite a first inner wall of said housing.
 24. The swivel assembly of claim 23, wherein when said swivel rotates clockwise or counterclockwise with respect to said start position, said rod extends out of said housing and said piston moves toward said second inner wall of said housing, thus compressing said coil spring between said piston and said second inner wall of said housing.
 25. The swivel assembly of claim 24, wherein when said swivel is released, said coil spring becomes uncompressed and moves said piston away from said second inner wall of said housing, thereby retracting said rod into said housing and rotating said swivel back to its start position.
 26. A method for self-centering swiveling of a chair comprising: providing a swivel that comprises an actuator which self-centers and biases the swivel to a start or zero position; rotating said swivel from its start or zero position, thus compressing or tensioning said actuator; and releasing said swivel thus moving said actuator to bias and rotate said swivel back to said start or zero position. 